docs: def css_class_cycler():
      '''
      Return a dictionary keyed by ``EventType`` abbreviations, whose values are an
      iterable or cycle of CSS class names.
  
      '''
      FMT = 'evt-{0}-{1}'.format
      return defaultdict(default_css_class_cycler, (
          (e.abbr, itertools.cycle((FMT(e.abbr, 'even'), FMT(e.abbr, 'odd'))))
          for e in EventType.objects.all()
      ))